Academic Writer includes numerous tutorials for writing and APA style, but you can also use it as a hub to create a free account and save your work.
Grammarly is more of a revision tool, but you can compose/edit right inside the Grammarly window and check it for errors as you go.
Cite sources and send them to Google Docs to compose your work. NoodleTools is an excellent source for research-centered assignments. You can also complete early planning activities, such as outlines, and take notes on electronic notecards inside NoodleTools.